1. Field of the Invention
The present invention is a heat nozzle designed for use with a portable, handheld seam sealing welding gun for dispensing a molten sealant to join adjacent sheets of flooring.
2. Description of the Prior Art
In laying flooring that is sold commercially in sheets, such as linoleum flooring, adjacent sheets of flooring are positioned side by side and cut to the desired shape. The flooring sheets are secured to the floor by adhesive compound. To secure the flooring sheets to the floor, the compound is applied to the floor and the cut sheets of flooring are laid in position, one by one. Once each sheet of flooring is laid, the next adjacent flooring sheet is brought into position and pressed against the floor with the linear edges of adjacent flooring sheets residing in mutual side-by-side abutment.
One major problem with laying sheets of flooring in this manner is that the adhesive bond between the underside of the flooring sheets and the subfloor therebeneath is sometimes inadequate. Quite often areas of the sheets of the linoleum flooring will tend to separate from the subfloor when the adhesive bond between the subfloor and the flooring sheets deteriorates due to age, movement of the subfloor, or improper installation.
The separation of areas of flooring sheets from the subfloor is particularly pronounced at the seams between adjacent sheets of flooring. The edges of adjacent flooring sheets which are supposed to reside in firm, mutual abutment, will sometimes tend to rise slightly from the subfloor. This presents both an unsightly appearance and also leads to a significant deterioration of the floor because of the separation that occurs when the edges of adjacent sheets of flooring rise. When separation between adjacent sheets of flooring occurs in this way, moisture, dirt and debris often find their way into the crack that forms between the flooring sheets, thus leading to further deterioration of the floor.
In the floor installation trade the use of fusible plastics to form a seal between the abutting edges of adjacent sheets of flooring has gained increased popular acceptance. According to this technique adjacent sheets of flooring are moved into abutting relationship and a grooving tool is used to cut an upwardly facing, elongated groove where the abutting sheets of flooring meet. That is, the seams of the sheets of flooring are cut with a groove so that the exposed upper surface of each sheet covers a slightly smaller area than its concealed undersurface, thus providing adjacent surfaces forming a groove or channel between adjoining sheets of flooring. These adjacent surfaces can be bonded together using a fusible thermoplastic applied from above. The color of the thermoplastic is chosen to match the color of the flooring so as to render the demarcation between adjacent sheets of flooring largely undetectable.
For quite some time portable, handheld seam welding guns have been available commercially which melt sealant to seal floor seams. Conventional seam welding guns are typically electrically powered and melt a thermoplastic bead by means of resistance heating of hot air. The heated air is directed at the sealant to melt it in a melting chamber within a nozzle so that the molten sealant flows into the groove.
Handheld seam welding guns of this type are typically configured with a generally cylindrical body forming the rear portion of the gun and a heat conducting member projecting forwardly from the body along a longitudinal axis. Conventional, portable handheld seam welding guns of this type are manufactured in Europe by Leister Process Technologies, CH-6060 Sarnen, Switzerland. Other, comparable commercial seam welding guns are also available, such as the Zinser K-5 handheld welder that is available from Zinser Schweisstechnik GmbH, Stuttgarter Strasse 145, 73061 Ebersback/Fils, Stuttgart, Germany.
An adapter having a heat concentration nose, typically formed of a highly conductive metal, such as copper or a copper alloy, is mounted on the heat conducting member and includes a heating tip mounting tube. The heating tip mounting tube projects forwardly along the longitudinal axis of the body and has a narrow, tubular configuration. This type of adapter is often referred to in the trade as a “pencil tip” adapter. The heating tip mounting tube fits into the hollow heat welding nozzle.
A conventional, portable, handheld seam welding gun heat welding nozzle includes a hollow cylindrical sleeve that fits onto the heating tip mounting tube and another tubular structure that accommodates an elongated length or stick of thermoplastic that is fed into the interior of the heat welding nozzle and melted therein.
The nozzle construction is extremely important in order to achieve a smooth weld that will completely seal the seam but which will not damage the flooring. In recent years sheets of flooring having urethane finish coatings have gained in popularity. While quite attractive, such floorings are more sensitive to heat than floorings constructed completely of other materials, such as thermoplastic. As a consequence, many conventional heat welding nozzles damage the flooring finish by scorching or discoloring it.
A number of different nozzles are currently utilized to seal seams in sheets of flooring constructed of temperature sensitive materials. However, conventional nozzles used for this purpose are prone to scorch the flooring or discolor the edges of the flooring when melting the sealant into a groove between adjacent sheets of flooring. One typical welding nozzle that is utilized is sold by Janser GmbH located in Ehnington, Germany as the Ultra-Speed-Nozzle, Part No. 224 800 007. This same company also sells the Speed Weld Nozzle as Part No. 224 700 300. Laramy Products Co., Inc. located in Lyndonville, Vt. sells the Universal High-speed Tip that is sometimes used for welding seams between sheets of thermally sensitive flooring. The Zinser Company also sells the Super Rapid Nozzle that is sometimes utilized for the same purpose. However, all of these conventional nozzles produce mediocre results. All of them are prone to scorch the flooring and/or discolor the edges of the flooring sheets during the seam welding process.